@vv Here is an assuming version that works:

restart;

puzzle := sum(cos(k*Pi/(2*n + 1))^4, k = 1 .. n);

expand(convert(puzzle,exp));
simplify(%) assuming n::posint;

@vv This version works:

restart;
puzzle := sum(cos(k*Pi/(2*n + 1))^4, k = 1 .. n);
simplify(expand(convert(puzzle, exp)),assume=n::posint);

See simplify/details.

@janhardo I know how to make a screenshot.
I usethe special  PrtSc.

What I want removed is this whole thing:
 

@vv Thank you for the reference. Now i have Maple 2025.1.
I had tried Check for Updates in Maple 2025.0 a couple of times, but the answer was "No updates available".

@C_R After installing Maple 2025.1 I tried my worksheet made in 2025.0.

As you said it still doesn't work on that worksheet.

Then I tried copying the input lines and put them in a new fresh worksheet. Then both computations could be stopped.

@vv I'm not aware of the existence of Maple 2025.1. 
Maple 2025.0, however, cannot stop ifactor(x).
Maple 2024.2 can be stopped without problem.

So I certainly hope and expect that when the update 2025.1 comes it can stop that calculation.
 

@WD0HHU Are you sure you are seeing the whole bottom?

Take a look at these two screenshots.
The one is from the bottom left the other from the bottom right.

@Christopher2222 I agree, but that works (at least).

Notice that the Interrupt button in Maple 2025 is located at the bottom left of the screen (not in the file menu).
There are 2 buttons: Interrupt the current operation, Debug the current operation to the left of the text showing either Ready or Evaluating.
Unfortunately the Interrupt button doesn't work.
Try the uploaded worksheet below in Maple 2025, and in Maple 2024.
You cannot stop Maple 2025, but you can easily stop Maple 2024.

Interrupt_button_problem.mw 

Good question.

solve(x^n=0,x); # Zero
solve(x^n=0,x) assuming n<0;  # NULL
solve(x^n=0,x) assuming n>0;  # Zero
solve(x^n=0,x) assuming n=0;  # Null
0^0;  # 1
eval(x^n, {x=0,n=0}); # 1

Note:

0^(1/n);  # Returns unevaluated i.e. 0^(1/n)

@mmcdara  This also works in the very old Maple 12.

The problem is that it doesn't open in MaplePrimes, but in
https://bountygames.co.in/

The "post" is really just that link.

I have just tried to remove the post "Drive results with a top Google ads agency in the USA!"

It didn't work. It said "Error generating page".

I hope my first comment was not misunderstood!

I certainly didn't mean that the name Maple should be changed!

Using Firefox + duckduckgo I got this screenshot.

@acer The link works in Firefox for me too without signing in.